In recent semiconductor manufacturing technology, for example, in the case in which a silicon substrate is manufactured, the handling of special material gases (for example, silane gas, disilane gas, diborane gas, and the like) is extremely important, and an elucidation of the chemical and physical properties thereof would lead to great developments in such manufacturing technology. Such special material gases are corrosive, spontaneously combustive, and toxic; such properties make the handling thereof inconvenient, and they decompose as the result of specified temperatures or discharges; for example, in the case in which this special material gas comprises silane gas (SiH.sub.4), it is known that this gas decomposes into Si and 2H.sub.2, and the decomposition temperatures thereof have been measured.
Conventionally, the component analyses of such special material gases were carried out using concentration analyzers utilizing gas chromatography.
However, conventionally, only approximate values were known for the decomposition temperatures of special material gases, and no useful data could be obtained with respect to the relationship between various reaction conditions and variations in the decomposition rate. Accordingly, in particular with respect to manufacture of semiconductors having hyperfine structures, sufficient understanding of these relationships is necessary.
The present invention was created in light of the above-described problems in the background art; it has as an object thereof to provide a method and device for easily and accurately measuring the relationship between the decomposition rate of special material gasses which present difficulties in handling, and reaction conditions such as reaction time, impurity concentration, and atmospheric temperature.